Dispensers for viscous materials provided in containers such as cartridges or foil (“sausage”) packs, or viscous materials provided in bulk, are well known in the art. Such dispensers typically comprise a mechanism, for example an electric motor, which acts to advance a plunger towards a nozzle such that material is forced through the nozzle.
In certain applications, for example when dispensing a chemically reactive material, such as a material which hardens to anchor a component in place, it is desirable to be able to dispense a required amount of material from the dispenser sufficient for the application concerned. Such applications might be, for example, holding a stud in place in a wall. It is important to be able to dispense the correct amount of material from the dispenser in these applications since too much leads to unnecessary waste, whereas too little risks that the component is not sufficiently well anchored in place, resulting in the obvious safety implications.
One example of a known dispenser for chemically reactive materials involves dispensing material through a mixer from a plurality of containers, typically two, each container containing a different material.
It is also desirable to control the dispensing of material such that, once a required amount of material is dispensed, excess material does not drip from the nozzle of the dispenser. Such dripping also results in material wastage, for example.
Typically, there is a need to accurately control the mechanism to dispense material in a controlled manner.